Wire wrapping tool

ABSTRACT

A wire wrapping tool haVing a wrapping bit with a hole therein adapted to be received by a terminal stud, a wrapping sleeve in which the bit is mounted for limited telescoping movement. The bit has a wire relief flat adjacent a wrapping slot which merges into a tapered counterbore surrounding the end of terminal engaging hole.

United States Patent Ackerman 1 June 20, 1972 [54] WIRE WRAPPING TOOL I [72] Inventor: Daniel Whitney Ackerman, Binghamton,

[73] Assignee: Universal Instruments Corporation,

Binghamton, NY.

[22] Filed: Aug. 11, 1970 [21] App]. No.: 62,825

[52] 11.8. C1 ..140/1 18, 29/203 HM, 242/7.17, 140/124 [51] Int. Cl. .112" 7/00, B21f 15/00 [58] Field of Search ..29/203 H, 203 HM; 140/118, 140/119, 122, 123, 124; 242/706, 7.14, 7.17

[56] References Cited UNITED STATES PATENTS 2,585,010 2/ 1952 Hickman et a1. ..29/203 HM 2,758,797 8/1956 Mikiau ..242/7.17 2,885,764 5/1959 Shulters et a1 ..29/203 HM Primary Examiner-Charles W. Lanham Assistant Examiner-E. M. Combs Attorney-Fidelman, Wolffe & Leitner ABSTRACT A wire wrapping tool having a wrapping bit with a hole therein adapted to be received by a terminal stud, a wrapping sleeve in which the bit is mounted for limited telescoping movement. The bit has a wire relief flat adjacent a wrapping slot which merges into a tapered counterbore surrounding the end of terminal engaging hole.

14 Clains, l 1 Drawing Figures PKTE'N'TEDwnzo m2 3.870.784 sum 1 or 3 FIG. 3

INVENTOR. DAN IEL WHITNEY ACKER MAN PATENTEDJUHO 1972 SHEET 2 or 3 FIG. 5

WIRE WRAPPING TOOL This invention relates to a wire wrapping tool for use in a semi-automatic operation of wrapping wire leads around terminal studs. A wire wrapping tool usually includes a bit and a sleeve.

In manufacturing electrical and electronic equipment, it is desirable to interconnect terminals on the equipment, e.g., on printed circuit boards. It is usually done by wrapping the stripped ends of a measured length of insulated wire strand onto the terminals to form wrapped connections thereon. Most wrapping machines today accomplish such an operation at relatively high speeds.

In the process of wrapping wire leads around terminal studs, a partially stripped section of wire is placed either automatically or by a machine operator into engagement with a wrapping bit. The bit retracts up into a sleeve which locks the section of wire into the wrapping head. The retracted bit and sleeve then descend onto a preselected terminal stud and the head rotates, thus wrapping the wire securely around the stud.

Various wrapping bits and sleeves have been designed to accomplish such an operation and they are generally wellknown. The problems of wire wrapping, which still exist, center around achieving a proper wrap on the terminal stud.

There are generally two types of wirewraps. The first is the standard wrap" where there is no insulation involved in the wrapped spirals of the wire. The second is the modified wrap which provides two turns of insulation around the post prior to wrapping the stripped portion of the wire. While the subject matter of this invention deals primarily with the latter, it is understood that the instant invention can be adapted to provide a standard wrap."

One problem encountered has been the so-called spiral" wrap where the turns of wire taken around the terminal studs tend to loosen because of spaces between the turns, i.e., the successive turns should abut each other.

Another problem encountered in wrapping wire on a stud has been the opposite problem from that just previously described, i.e., the problem of overwrap. Overwrap is where one turn is taken around the post over turns already there, causing overlap and looseness in the connection.

Open wrap is still another unacceptable result in wrapping terminals. This is where the turns are grouped, i.e., several turns are made in proper fashion and then the next turn is spaced considerably apart. This leaves an open gap in the wrap.

Other problems are the absence of sufficient turns of insulation around the base of the stud and the pigtail left by the end of the wire projecting out from the side of the stud after the wrapping is completed.

All of these problems and more are caused by wrapping bits which are not properly designed. Too large a wrapping radius, an improper wire guiding radius, slippage or binding between the bit and the sleeve and other considerations cause bad wraps as previously discussed.

A proper modified wrap is where a bit will tightly wrap about one and a half to two turns of the unstripped wire around the stud, then tightly wrap the remaining stripped wire around the stud so that each turn abuts the next and the end of the wire is left flush against the stud. When such a wrap is accomplished, a cold weld actually takes place between the wire and stud when the wire is wrapped. The studs are usually square in cross-section so that the comers are actually welded to the wire because of the high pressure with which the wire is wrapped.

This tooling of this invention overcomes all the difficulties discussed and insures a proper, tight and acceptable wrap. The bit of the present invention has a flat wire bearing surface merging with a relieved wire slot which cooperates with a flange on the sleeve to securely and accurately hold the wire as it is being fed onto the stud as the head rotates. The slot is a U-shaped configuration to properly support the length of the portion of wire within the slot to insure proper presentation of the wire to the bit, i.e., to guide the wire into position.

Accordingly, it is an object of the present invention to provide a new and improved wire wrap tool.

Another object of this invention is to provide an improved wrapping tool to accurately and reliably provide acceptable wire wraps on a terminal stud.

A further object of this invention is to provide an improved wrapping tool for insuring proper presentation of the wire to the wrapping bit. v

A further object of this invention is to provide the proper I amount of tension in' the spiral portion as the wire is being wrapped, i.e., not too loose or too tight.

With these and other objects in view, reference is had to the accompanying drawings in which:

FIG. I is a perspective view of the wrapping bit of this invention;

FIG. 2 is a perspective view of the wrapping sleeve of this invention;

FIG. 3 is a side view of the wrapping bit of FIG. 1;

FIG. 4 is an end view of the assembled bit and sleeve of FIGS. 1 and 2;

FIG. 5 is a sectional view of the wrapping bit and sleeve in assembled relation and in the process of securing a wire onto a terminal stud;

FIG. 6 is a partial sectional view of a modified bit countersink;

FIG. 7 is a partial sectional view of another modified countersunk bit;

FIG. 8 is a front view of the wrapping bit and sleeve in assembled relation;

FIG. 9 is a schematic end view of the tool showing the geometry of the wire slot;

FIG. 10 is an end perspective view of the tool partially cut away showing a modified counterbore arrangement;

FIG. 11 is a partial sectional side view of the tool of FIG. 10

taken along lines 10 -I0.

Referring now to FIG. I, there is shown the wrapping bit I of the present invention. It is cylindrical in cross-section. At one end it is notched as at 12 and adapted to be received by a rotary chuck. A second notch adjacent the opposite end provides a flat surface I1 and end walls 10 and 19. The end portion has a stud engaging hole 14 which may terminate in tapered portion 15 (See FIG. 3). The hole 14 is countersunk as at 16 to provide stud lead-in guide surface.

A wire slot connects the countersunk portion 16 with flat surface 11. The slot consists of a relieved groove 20 terminating in a gradually merging area 21 with flat surface 11. The slot forms a wall 17 which terminates in a curved surface 18 which connects with wall I9. Wall 17 and the slot form an edge 22 where they merge with countersink 16.

As shown in FIG. 4, countersunk surface 16 has a relieved notch 23 which merges with groove 20 to fonn a gradually curved transition surface for the wire to be guided out of the slot and around the terminal studs. This notch geometry is similar to that shown and discussed in US. Pat. No. 3,006,563.

FIG. 2 shows the sleeve 2 of the present invention. It is generally tubular having a flat end edge 25 which is substantially perpendicular to the longitudinal axis of the sleeve. The sleeve has an inside diameter sufficient to accommodate the wrapping bit.

The sleeve has a slot therein defined by straight edge 3, curved edge 4, and straight edge 5 which slopes upwardly as at 6 to a flange edge 7.

The sleeve 2 and bit 1 are secured together for relative telescoping movement by pin 13 in bit 1 which is received in slot 8 (FIG. 5) in sleeve 2.

As shown in FIG. 8, the flange portion containing edge 7 extends above the level of flat surface 11 which is on the same plane with edge 3. The inner surface 24 of the sleeve flange cooperates with wall 17, as shown in FIG. 4, to form a passage for the wire.

As shown in FIG. 5, the assembled bit I and sleeve 2 are shown in the process of wrapping a wire 35 about a square terminal stud 31 which is secured to a circuit board 30. A portion of the wire has insulation 36 thereon which terminates at 37. Stud 31 can have a pointed end 32 which is adapted to initially engage tapered area 16 (See FIG. 1) and guide the stud into the receiving hole 14 (See FIG. 1).

The operation of the device is as follows. The sleeve 2 is in retracted position when the operator or automatic feeding device (not shown) lays the wire across the flat surface 11. The bit 1 is retracted up into the sleeve 2. As the retraction takes place, the forward edge 27 (FIG. 2) of the sleeve flange portion forces the wire to pivot around curved comer 18 against wall 17. Continued retraction forces the wire down into groove where it is held by wall 17 and the inner surface 24 of the sleeve 2. The end of the wire is forced away from the center line of the bit 1 by area 21 and projects outwardly through the slot in the sleeve 2.

The tool is rotated and the end of the wire containing the insulation is wrapped around the stud. The tool is further rotated and the wire, by guiding notch 23, is wrapped around stud 31.

The bit is biased downwardly to maintain pressure on the wire but it is the torque on the wire portion that is out of the slot and not yet wrapped on the stud that insures that the wire is securely wrapped around the stud in proper fashion rather than surface 16 engaging the wire. As the wire is wrapped around stud 31, the bit is forced upwardly. The tool can be resiliently connected to allow upward movement as it rotates.

FIGS. 6 and 7 show two alternate designs that surface 16 may take for controlling the wrapping of the tail or end of the wire. FIG. 6 shows a design with a bit 40 with a hole 41 having a countersunk portion 43, a counterbored portion 44, and a further countersunk portion 45. FIG. 7 shows a bit 30 and sleeve 31, bit 30 having a hole 32 which terminates in a countersunk surface 33. Surface portion 33 has an axis which is not coincident with the angle of the bit but is inclined thereto at an angle of The wrapping tool of the instant device provides an improved wrap of proper tightness and more uniform characteristics. Further, the groove in the bit and the flange on the sleeve cooperate to define a wire feeding passage which is near the rotational axis of the bit which is important since the wire is not unduly stressed and a more uniform wrap of proper tightness is achieved. The U-shape of the slot and the merging notch also provide for a smoother feed of the wire. The shape of the slot and notch also provide for a smooth feed of the wire without creating undue stress and fatigue therein.

The particular arrangement of the flat surface 11 with edge 3 of the sleeve slot and the relationship of the sleeve flange and rounded comer 18 afford an easy bending of the wire into groove 20 as the bit is retracted. There is no necessity for relieved or cut-away areas to allow the wire to bend or pivot. The sleeve provides no obstruction to the wire pivoting across surface 11 as the bit is retracted.

Referring now to FIG. 9, there is shown a diagrammatic view of the end of a bit 50. The flat surface 54 is shown by dotted lines.

The wire feeding groove is designated as 57 and has a wall portion 58. To arrive at the proper position and size of the groove in relation to the axis of presentation of the tool to a stud to be wrapped, the center of the curved portion of the groove is placed along a radial line at 45 to the axis of presentation. It can be placed on either side thereof depending on whether a right-hand or left-hand is desired. This, naturally, places it in a radial position so that X y along the axes of presentation.

Next, the size of wire to be wrapped is selected. The diameter of a wire, with its insulation 70, is placed along the 45 line until its circumference protrudes out beyond the circumference of the bit 50. The amount of protrusion is shown by B and is approximately in the range of 0.001 0.003 inch so as to provide an interference fit with the sleeve. This procedure establishes point F and the radius of the wire with its insulation thereon is designated as r. The radius of the curved portion of groove 57 is designated as r'. Generally, r r +0.002 in. This added 0.002, designated as C, has been found through experimentation to be most satisfactory for feeding the wire. both the insulated portion and the stripped portion. The relationship of the stripped portion to the groove as it is being fed is designated as 62.

It should be noted that by selecting the groove size in the aforementioned manner, the plane of flat surface 54 intersects the intersection 59 of the groove and the circumference of the bit 50. Also, the distance A, as shown in FIG. 9, is equal to the diameter of the insulated wire 70.

A notched area 60 is provided in a manner similar to notch 23. Area 60 intersects groove at 61 as shown in FIG. 9. The area 60 provides a guide and a bending radius for the wire as it feeds and wraps onto a stud.

As shown in FIG. 10, bit 50 has end face 56, a stud receiving bore 51, a countersunk area 52, a counterbored area 53 and a further countersunk area 55.

The stripped wire 62 is shown in groove 57 being fed onto stud 65 resulting in spiral wire portion 62. The wire, as it passes over portion 61, does not completely follow the radius 60. It flows out into space at an angle a. The angle the radius can bend the wire can vary from 0 to The wire is thus under three dimensional torque from point D to point E, the torque being caused by the relationship of groove 57 to the stud 65 and the shape of area 60 and portion 61. The portion 61 only puts enough torque on the wire to allow radius 60 to influence the bendings of the wire as it goes into space.

Referring now to FIG. 11, the wire 62 is shown in the same position as in FIG. 10. A further modification is shown, however, and that is the relieving of counterbore 53 in cases where a certain gauge wire or different material is being wrapped. A relieved area 63 is provided which merges with counterbore 53, groove 51 and area 60. The relieved area 63 is provided with a curved camming portion 64. Portion 64 is shaped so as to engage the end of stripped wire portion 62 and whip it onto stud 65, thus eliminating any pigtail" in the wrap. This surface does not effect the wire as it is being wrapped, however.

As is shown, the relieved area 63 does not merge with countersunk area 52.

As shown in FIGS. 10 and 11, point E is where the spiral portion 62' begins and the torque, for all intents and purposes, dissipates at this point.

While countersunk area 52 does not effect the wrap as the wire is being fed, it is understood that the bit is biased downwardly to offset the upward thrust on the bit by the torqued portion (D to E) of the wire. At the conclusion of the wrap, the tool is allowed to be biased downwardly so the countersunk area 52 in conjunction with portion 63 and 64 engages the top of wrapped wire 62 and guides and compresses the last spiral.

Control of the operational sequence of the tool and wire feed can be accomplished in any of a number of conventional ways, e.g., a punched tape NC control system may be used for directing the various operational steps. A cam system and solenoids whose sequence is controlled by the cam system and a motor driven cam shaft may be used. A closed loop digital control system using D.C. servo motors may be a further way of automatically running the sequence of operations.

It is understood that the wrapping tool shown and described is merely illustrative of this invention and other modifications and changes will occur to those of ordinary skill in the art without departing from the scope of the appended claims.

What is claimed is:

I. A wire wrapping tool for wrapping connection leads onto terminal studs comprising:

a. a tubular sleeve member; and

b. a cylindrical bit received in said sleeve member and adapted to move longitudinally therein;

c. said bit having a bore in one end for receiving a terminal,

said bore being recessed and located along the longitu dinal axis of said bit; and

d. a flared concentric surface means between the end of said bit and the beginning of said bore; and

. an external groove means in said bit, one end of which merges with said flared surface means, the merger of said groove means and surface means being relieved so as to form a wire guiding notch means, and said groove defining a wire supporting wall; and

f. a planar surface formed in said bit so as to form a notched area having two opposed end walls; and

said groove means merging with said planar surface, the

merger of said wire supporting wall of said groove and one of said opposed end walls being relieved to form a rounded corner means adapted to allow a wire to be pivoted into said position as said bit retracts into said sleeve and said groove means having its bottom portion beneath the plane of said notched area; and

h. said sleeve having an elongated opening therein which cooperates with said planar surface to allow a wire to be pivoted upon retraction of said bit within said sleeve; and

i. flange means on said sleeve adapted to overlie said groove means when said bit is retracted and to cooperate with said wire supporting wall of said groove to define a wire supporting passage; whereby when a wire is laid across the planar surface, retraction of said bit within said sleeve causes the wire to pivot on said corner means and is grasped in said groove between said flange means and said wire supporting wall.

2. A wire wrapping tool as in claim 1 wherein said groove is relieved so as to gradually merge with said planar surface, whereby a wire held in said groove has its end portion directed up off said planar surface and out through said elongated passage in said sleeve means.

3. A wire wrapping tool as in claim 1 wherein said flared surface means comprises a countersunk area between the end of said bit and the beginning of said bore.

4. A wire wrapping tool as in claim 1 wherein said flared surface means comprises a first countersunk surface, a counterbore surface and then a second countersunk surface between the beginning of said bore and the end of said bit.

5. A wire wrapping tool as in claim 1 wherein pin and slot means are provided on said bit and sleeve to prevent relative rotation therebetween.

6. A wire wrapping tool as in claim 1 wherein said groove means has an arcuate portion, the radius of said arcuate portion being slightly larger than the diameter of the insulation of the wire to be wrapped.

7. A wire wrapping tool as in claim 1 wherein said groove means is of a size whereby the diameter of the insulation of the wire to be wrapped protrudes out beyond the peripheral surface of the bit.

8. A wire wrapping bit as in claim I wherein the plane of the planar surface intersects the intersection of an arcuate portion of said groove means and the peripheral surface of said bit.

9. A wire wrapping tool for wrapping wires onto terminal studs comprising:

a. a tubular sleeve member;

b. a cylindrical bit received in said sleeve member and adapted to move longitudinally therein;

c. means to prevent relative rotation between said bit and sleeve;

d. a stud receiving passage in said bit, said passage being located along the longitudinal axis of said bit;

e. a concentric counterbore in said bit of larger diameter than said passage and located between the end of said bit and said passage, a portion of said counterbore being relieved and providing a camming surface;

. an external wire receiving groove means in said bit, one end of said groove means merging with said relieved portion of said counterbore, the merger of said groove means and relieved counterbore portion being further relieved to provide a wire guiding notch means and said groove defining a wire supporting wall;

g. a planar surface formed in said bit so as to fonn a notched area having two 0 posed end walls; h. the other end 0 said groove means merging with said planar surface, the merger of said wire supporting wall of said groove and one of said end walls being relieved to form a rounded comer means adapted to allow a wire to be pivoted into position as said bit retracts into said sleeve and said groove means having its bottom portion beneath the plane of said notched area;

i. said sleeve having an elongated opening therein which cooperates with said planar surface to allow a wire to be pivoted upon retraction of said bit within said sleeve;

j. flange means on said sleeve cooperating with said wire supporting wall to define a wire supporting passage; whereby when a wire is laid across said planar surface, retraction of said bit within said sleeve causes the wire to pivot on said comer means and it is grasped in said groove means between said flange means and said wire supporting wall and said camming surface forces the end of said wire to lie flat on said stud at the conclusion of said wrapping.

10. A wire wrapping tool as in claim 9 wherein said groove is relieved so as to gradually merge with said planar surface, whereby a wire held in said groove has its end portion directed up off said planar surface and out through said elongated passage in said sleeve means.

1 l. A wire wrapping tool as in claim 9 wherein pin and slot means are provided on said bit and sleeve to prevent relative rotation therebetween.

12. A wire wrapping tool as in claim 9 wherein said groove means has an arcuate portion, the radius of said arcuate portion being slightly larger than the diameter of the insulation of the wire to be wrapped.

13. A wire wrapping tool as in claim 9 wherein said groove means is of a size whereby the diameter of the insulation of the wire to be wrapped protrudes out beyond the peripheral surface of the bit.

14. A wire wrapping bit as in claim 9 wherein the plane of the planar surface intersects the intersection of an arcuate portion of said groove means and the peripheral surface of said bit. 

1. A wire wrapping tool for wrapping connection leads onto terminal studs comprising: a. a tubular sleeve member; and b. a cylindrical bit received in said sleeve member and adapted to move longitudinally therein; c. said bit having a bore in one end for receiving a terminal, said bore being recessed and located along the longitudinal axis of said bit; and d. a flared concentric surface means between the end of said bit and the beginning of said bore; and e. an external groove means in said bit, one end of which merges with said flared surface means, the merger of said groove means and surface means being relieved so as to form a wire guiding notch means, and said groove defining a wire supporting wall; and f. a planar surface formed in said bit so as to form a notched area having two opposed end walls; and g. said groove means merging with said planar surface, the merger of said wire supporting wall of said groove and one of said opposed end walls being relieved to form a rounded corner means adapted to allow a wire to be pivoted into said position as said bit retracts into said sleeve and said groove means having its bottom portion beneath the plane of said notched area; and h. said sleeve having an elongated opening therein which cooperates with said planar surface to allow a wire to be pivoted upon retraction of said bit within said sleeve; and i. flange means on said sleeve adapted to overlie said groove means when said bit is retracted and to cooperate with said wire supporting wall of said groove to define a wire supporting passage; whereby when a wire is laid across the planar surface, retraction of said bit within said sleeve causes the wire to pivot on said corner means and is grasped in said groove between said flange means and said wire supporting wall.
 2. A wire wrapping tool as in claim 1 wherein said groove is relieved so as to gradually merge with said planar surface, whereby a wire held in said groove has its end portion directed up off said planar surface and out through said elongated passage in said sleeve means.
 3. A wire wrapping tool as in claim 1 wherein said flared surface means comprises a countersunk area between the end of said bit and the beginning of said bore.
 4. A wire wrapping tool as in claim 1 wherein said flared surface means comprises a first countersunk surface, a counterbore surface and then a second countersunk surface between the beginning of said bore and the end of said bit.
 5. A wire wrapping tool as in claim 1 wherein pin and slot means are provided on said bit and sleeve to prevent relative rotation therebetween.
 6. A wire wrapping tool as in claim 1 wherein said groove means has an arcuate portion, the radius of said arcuate portion being slightly larger thAn the diameter of the insulation of the wire to be wrapped.
 7. A wire wrapping tool as in claim 1 wherein said groove means is of a size whereby the diameter of the insulation of the wire to be wrapped protrudes out beyond the peripheral surface of the bit.
 8. A wire wrapping bit as in claim 1 wherein the plane of the planar surface intersects the intersection of an arcuate portion of said groove means and the peripheral surface of said bit.
 9. A wire wrapping tool for wrapping wires onto terminal studs comprising: a. a tubular sleeve member; b. a cylindrical bit received in said sleeve member and adapted to move longitudinally therein; c. means to prevent relative rotation between said bit and sleeve; d. a stud receiving passage in said bit, said passage being located along the longitudinal axis of said bit; e. a concentric counterbore in said bit of larger diameter than said passage and located between the end of said bit and said passage, a portion of said counterbore being relieved and providing a camming surface; f. an external wire receiving groove means in said bit, one end of said groove means merging with said relieved portion of said counterbore, the merger of said groove means and relieved counterbore portion being further relieved to provide a wire guiding notch means and said groove defining a wire supporting wall; g. a planar surface formed in said bit so as to form a notched area having two opposed end walls; h. the other end of said groove means merging with said planar surface, the merger of said wire supporting wall of said groove and one of said end walls being relieved to form a rounded corner means adapted to allow a wire to be pivoted into position as said bit retracts into said sleeve and said groove means having its bottom portion beneath the plane of said notched area; i. said sleeve having an elongated opening therein which cooperates with said planar surface to allow a wire to be pivoted upon retraction of said bit within said sleeve; j. flange means on said sleeve cooperating with said wire supporting wall to define a wire supporting passage; whereby when a wire is laid across said planar surface, retraction of said bit within said sleeve causes the wire to pivot on said corner means and it is grasped in said groove means between said flange means and said wire supporting wall and said camming surface forces the end of said wire to lie flat on said stud at the conclusion of said wrapping.
 10. A wire wrapping tool as in claim 9 wherein said groove is relieved so as to gradually merge with said planar surface, whereby a wire held in said groove has its end portion directed up off said planar surface and out through said elongated passage in said sleeve means.
 11. A wire wrapping tool as in claim 9 wherein pin and slot means are provided on said bit and sleeve to prevent relative rotation therebetween.
 12. A wire wrapping tool as in claim 9 wherein said groove means has an arcuate portion, the radius of said arcuate portion being slightly larger than the diameter of the insulation of the wire to be wrapped.
 13. A wire wrapping tool as in claim 9 wherein said groove means is of a size whereby the diameter of the insulation of the wire to be wrapped protrudes out beyond the peripheral surface of the bit.
 14. A wire wrapping bit as in claim 9 wherein the plane of the planar surface intersects the intersection of an arcuate portion of said groove means and the peripheral surface of said bit. 